The present invention relates generally to sheet metal feed mechanisms and particularly to a cradle straightener feeder for heavy gauge and high-strength sheet steel.
Prior art sheet metal feeder mechanisms utilize a coil of sheet metal mounted on a powered spindle having a coil hold-down roll and need a second motorized hold-down roll for traction. Traditional coil loading and threading devices have top feed uncoilers, powered coil hold-down rolls, a powered coil cushioning device, an extendable peeler, and a powered dekinker or decurler. These devices, however, have required on the order of thirty to thirty-five discrete operator sequence events to load and commence operation of the device, each of which events usually require approximately thirty seconds per event. Some of the operator sequence events have to be repeated two or more times to accommodate coil-to-coil mechanical variations. The present invention eliminates at least five distinct conventional operator sequence events per coil change at the time of coil change, with a reasonable expectation of time savings of at least two-and-a-half minutes per coil change and often a time savings of five or more minutes per coil change, such as the extension and retraction of a separate coil cushioning device, extension and retraction of a separate extensible peeler (plus the positioning of the peeler), and moving a separate, powered dekinker or decurler apparatus upwardly and downwardly. The present invention is generally loaded and commencing operation in at most fifteen operator sequence events, with many of the traditional steps and apparatus integrated into the novel constructions of the present invention.
The present invention also has an object of utilizing the weight of a coil to act as an advantage in a cradle feeder by using bottom of coil payoff, eliminating the necessity of having a coil hold-down roll and any redundant second motorized hold-down rotation roll for traction. A further object is to use the forces in the coil to cause the outer wrap of the coil to break away from the outside diameter of the coil. A further object is to control the position of this break away event by positioning the leading edge of the coil at a desirable point relative to the lower outgoing driven cradle roll so that only that portion of the outer coil wrap will spring away from the coil outside diameter, and only at a controlled and desired time.
It is an additional object of the present invention to have the leading edge of the coil being threaded always visible to the operator from the outside diameter of the coil to at least the input pinch rollers of the combination staightener feeder.
A series of advantages of the present invention further evolve from the use of a powered pivoting threader bar and roller to provide several different functions. The bar may direct the leading edge of the coil toward the entry pinch rollers of the straightener feeder and control the leading edge of the coil over a coil curvature removal roller, thereby flattening the leading edge for acceptance into the input pinch rollers of the straightener. The threader bar can also act as a coil containment device which in most cases will eliminate the common practice of containing a coil by putting a bar through the inside diameter of the coil and into anchor slots or holes in either the side plate, machine frame, or both. Also, the threader bar in combination with the removal roller can be employed to decurl the trailing end of a coil roll for easier acceptance by the input rolls of the straightener and preclude a double coil thickness from being rolled over and pulled into the straightener with the attendant possibility of substantial damage and down time. The threader bar also may act as a coil cushion stop to protect the cradle roll bearings from impact shock during loading due to the coil rolling into the cradle from a coil storage and feeding ramp or other loading mechanism.
The present invention also has the object of providing adjustable straightener feeder pass line height adjustment to be capable of using the straightener feeder with any height compatible with a desired accessory unit, such as a shear and stacking unit, a conveyor, a press, or whatever selected accessory unit into which the sheet metal from the coil is fed.
Within the cradle holding the coil, the present invention has the object of providing adjustable cradle side plate coil guides. With both side plates adjustable, accommodations may be made for variations in coil width and assuring proper alignment with any selected compatible accessory unit.
A further object of the present invention is to incorporate a variable speed and variable torque main power transmission gear box. Such an arrangement enables the feed capacity of the unit to be greatly increased with regard to additional thickness, material strength, or width increases of the sheet metal in the coil over a standard geared unit. Such a unit can be cost-effective and desireable even with the speed sacrifice that may result as a trade-off when the variable torque gear box variation of the present invention is selected.
The cradle area also has the object of providing a protective finish, lubrication, or other desired liquid coating to the sheet metal coil via a roller coater incorporated within the cradle drive mechanism for the sheet metal coil. A protective coating may be utilized, for example, when an interface for protecting more critically finished materials is desired.
The present invention has the further object of creating a relationship of straightener rollers to the pass line of the material that requires a low bend rate with regard to the coil of material being fed. The present invention, with its low bend rate, does not require the steel to reach its yield point in order to pass into the straightener area of the machine where it is worked prior to feeding to an accessory unit. Also, low energy requirements exist due to the geometry of the cradle roll with regard to the straightener rollers to provide a significant cost savings when compared to prior art devices. Generally, the present invention drives the coil with a controlled acceleration, deceleration and velocity formulating an accurate feed progression with non-accumulating error.
The input pinch rollers and output feed rollers of the present invention also have a protective feature in case a curled trailing end of the coil reaches the pinch or feed rollers without the machine successfully decurling the trailing end or if a wide variation might exist in a sheet metal coil, which variation might damage the pinch or feed rollers. A cross-over check relief valve attached to a hydraulic cylinder mechanism which also provides an operating force to the pinch and feed rollers permits the upper pinch roller or upper feed roller to be jogged upwardly out of engagement with the main body of the sheet metal fed into the straightener feeder. Such a protective feature prevents damage to the pinch or feed rollers from double thickness material being inadvertently fed into the straightener feeder.
Essentially then, the present invention offers a compact, cost-effective mechanism enabling coil automation in the press shop without costly plant rearrangement, particularly in not requiring relocation or use of pit mounted presses. Units of the present invention can reduce the floor space requirements by seventy-five percent compared to traditional installations. A typical unit of the present invention will be somewhat less than three times the maximum coil diameter in length and approximately twice the maximum coil width in its width.
The present invention is designed to accommodate a broad range of metal thicknesses, widths and velocities with certain special operator conveniences, facilitating rapid loading and threading of new coils through the device and into the accessory application.
The present invention takes a lot less space, does not require a pit, is one unit (no alignment problems), is easy to align and install, and is extremely simple to operate. The simplicity is essentially due to the fact that fewer moving parts exist than conventional units (providing fewer and simpler operator controls with equal or greater levels of sophistication), the operator's view of many of the essential functions is unobstructed, and the present invention provides the shortest automated coil-threading path of any comparable system in the industry.
The present invention has an even further object of providing a joggle feeding mechanism to simultaneously feed forwardly and cross feed laterally. The joggle feed has the advantage of economy in material cost by feeding a single station blank die press or other similar single station accessory unit in a manner that results in a double die configuration producing much less scrap material. This is particularly useful when feeding heavy gauge material where the flexibility of movement of the material itself is minimal.
Other objects and advantages of the instant invention will be apparent in the following specification, claims and drawings.